1. Field of the Invention
The present invention relates to adjustable wrenches, and more particularly pertains to adjustable wrenches of the type having a stationary jaw formed at an end of a handle and a slidable jaw mounted for linear reciprocal movement toward and away from the stationary jaw by a worm gear in mesh with a gear rack on the slidable jaw. These conventional forms of wrenches must be precisely adjusted for conformance with the head of a fastener to be rotated. In order to avoid rounding off the fastener head, the worm gear must be rotated manually when the wrench is placed into engagement with the head of each fastener. Subsequently, the worm gear must be rotated in an opposite direction to allow disengagement of the wrench from the fastener head. In order to overcome these problems, the present invention provides a pivotal lever which causes axial movement of the worm gear to effect tightening and release of the slidable jaw sufficiently to allow engagement and disengagement of the wrench in an expedient manner.
2. Description of the Prior Art
Various types of adjustable wrenches are known in the prior art. A typical example of such an adjustable wrench is to be found in U.S. Pat. No. 2,112,193, which issued to J. Geddes on Mar. 22, 1938. This patent discloses an adjustable wrench which utilizes a worm gear and gear rack mechanism. U.S. Pat. No. 2,534,985, which issued to M. Napier on Dec. 19, 1950, discloses a sliding jaw wrench which utilize a compound pivotal linkage to tighten a V-shaped slidable jaw. U.S. Pat. No. 3,564,956, which issued to B. Landen on Feb. 23, 1971, discloses a locking flier type wrench which utilizes a compound pivotal linkage to tighten a sliding jaw into engagement with the head of a fastener. U.S. Pat. No. 3,659,485, which issued to A. Roth on May 2, 1972, discloses an adjustable open end wrench having one jaw member pivotally attached to a handle and a second jaw member slidably received by the handle juxtaposed the pivotal jaw. The sliding jaw is spring biased out of the handle and into a closing relationship with the fixed jaw. U.S. Pat. No. 3,926,077, which issued to S. Nordgren on Dec. 16, 1975, discloses an adjustable wrench which utilizes a worm gear and gear rack mechanism to close a slidable jaw relative to a stationary jaw. The wrench head is pivotally mounted at the end of the handle to provide a ratchet action.
While the above mentioned devices are directed to adjustable wrenches, none of these devices disclose a wrench in which a slidable jaw movable by a worm gear in mesh with a gear rack on the slidable jaw has a pivotal lever mechanism operative to effect axial movement of the worm gear. Inasmuch as the art is relatively crowded with respect to these various types of adjustable wrenches, it can be appreciated that there is a continuing need for and interest in improvements to such adjustable wrenches, and in this respect, the present invention addresses this need and interest.